Crystal holder



March 8, 1949. w, KUENSTLER 2,464,046

CRYS TAL HOLDER Filed 001:. is, 1947 Patented Mar. 8, 1949 UNITED STATES PATENT OFFICE 7 Claims.

This invention relates to crystals of the character employed in radio and electronics, such as crystals of quartz, tourmaline, or other piezoelectric material, and one of the objects of the present invention is to provide an improved mounting and housing means for crystals of this character.

An important object of the invention is to provide means by which a crystal may be resiliently supported within a suitable housing and protected against the effects of dampness, vibration and the elements, all of which tend to reduce the activity of the crystal and in raising or lowering of the natural frequency.

The invention further contemplates the provision of a crystal-supporting and housing means in which the several elements of the improved structure may be readily assembled; in which the crystal will be supported and protected; and in which the fusible joinder of leads or wires to the electrodes or metallic-coated faces of the crystal will be rendered unnecessary and other advantages secured as will be readily apparent to those skilled in this art.

More particularly, the invention contemplates the provision of a supporting means in which a crystal is clampingly held between the flanged edge portions of a pair of cupped metallic disks, and the crystal and the disks between which the crystal is sandwiched are clamped between a pair of spring fingers, the latter being suitably connected to contact means located outside of the casing in which the crystal and disks are contained.

In the accompanying drawing, wherein an illustrative embodiment of the invention is disclosed, Fig. l is a vertical sectional view through the crystal holder; Fig. 2 is a vertical sectional view throu h the same at right angles to the view of Fig. 1; Fig. 3 is a side elevational view of the holder; Fig. 4 is a face view of one of the crystal-clamping plates, looking at the outer or convex face of the same, and Fig. 5 is a sectional view taken on the line 5-5 of Fig. 4, looking in the direction of the arrows.

Referring to the drawing I indicates the base portion of the holder, the same consisting of a disk or substantially circular block of insulating material provided with a downwardly-extending substantially cylindrical plug portion 5 of insulation preferably formed as an integral extension of the base i. At the tip or extremity of the plug portion 5 is attached a metal cap 6, constituting a contact member when the plug portion 5 is entered into a suitable socket or receptacle intended for it. An annular groove 1 is provided in the cap 6 for engagement by a suitable spring element in the socket to thereby retain the plug portion 5 in the socket.

A stem 8 of metal extends axially through the center of the plug portion 5 and through the base member I and one end of the stem 8 is attached to the cap *5. The opposite end of the stem 8 is secured to a lateral foot portion 9 at the end of a vertically-disposed spring finger I0,

Surrounding the plug portion 5 and embedded therein sufficiently to cause its outer face to lie flush with the surface of the plug portion, is a metallic ring or sleeve II, which constitutes a contact member and is adapted, when the plug portion is entered into its socket or receptacle as heretofore mentioned to be engaged by a, suitable spring element constituting a contact in the socket. The ring or sleeve H is spaced from the cap 6 and is thus insulated therefrom and is provided with an extension in the form of a spring finger [2, which extends upwardly through and beyond the top of the base I. The two spring fingers I0 and I2 constitute supporting elements for the crystal l5 and the metallic plates or disks l3 and 14 between which the crystal is clampingly held.

The crystal I5 is relatively thin, particularly if it is of the very high frequency type, and is metallic-coated on both of its faces in the known manner, these metallic coatings constituting the electrodes for the crystal, this practice being well known in this art. In the form shown, the metallic-coated crystal is a circular disk and is p0- sitioned between the two disks l3 and I4, and the crystal unit thus provided, composed of the crystal l5 and the two disks l3 and I4, is clamped between the spring fingers l0 and I 2 in the manner clearly shown in Figs. 1 and 2.

The two metal disks l3 and I 4 are similar in shape and construction and are cupped or dished, being thus provided with a concavo-convex central area 20, formed with a central depression or recess l1 adapted for engagement by a detent portion l8 provided near the free end of each of the spring fingers l3 and I4. Adjacent to its marginal edge, each of the disks l3 and M is formed with a flat, annular flange l6, and when the tWo disks l3 and 14 are faced with their concave faces disposed toward one another with the crystal it between them, these flanges 16 f the two disks are in contact with the respective metallic-coated faces of the crystal near the peripheral edges of the crystal, as clearly seen in Fig. 2. When the two disks are placed together with the concave faces directed toward one another, it will be observed that only the flanges l6 contact with the crystal, or in other words, the crystal is clampingly held between the flanges it only of the disks l3 and it.

To facilitate this clamping action and yet prevent undue strain on the crystal, I form the flanges it into a plurality of separate clamping fingers 22, by radially slotting the plates 53 and I4 inwardly from their marginal edges as indicated at 2 l. These radial slots 2i are preferably, but not necessarily, uniformly spaced apart, thus providing a number of the clamping fingers 22 which, being resilient, can adapt themselves to inequalities in the crystal and prevent the imposition of undue pressure or that likely to break the crystal.

From the foregoing, the construction of the improved crystal holder will be readily apparent. The crystal i5 is of circular shape and of substantially the same diameter as that of the metal disks iii and Ml and it is placed between the two disks in. the manner shown. The unit thus produced, and consisting of the crystal Iii sandwiched between the two disks l3 and i l and clamped between the flange portions iii of the disks, is placed between the two spring fingers It and 2. The detents is of the fingers engage in. the depressions or recesses H in the disks and thus hold the disks centrally. The fingers it and I2, when thus engaging the disks, are under tension, and since these fingers normally tend to spring for a limited distance toward one another, they force the disks into clamping relation with the crystal interposed between them, thus firmly holding the crystal in place between the disks. Since the disk is is in contact with one of the coated or electrodes of the crystal, electrical contact is thus established through said disk with the finger as that is connected to the cap 6 through stem 8. In similar manner, disk Ed is in contact with the second coated face of the crystal it thus establishes electrical contact with the finger 52 extending from the ring of sleeve ii. This arrangement is such that it will be obvious that when the plug portion 5 is in serted a suitable socket or receptacle intended for its reception, the contact members 5 and H will establish electrical contact with suitable engaging elements on the socket, which elements are connected into the circuit of which it is in.- tended that the crystal shall form a part. The arrangement above described is one that enables the c ystal disks to be very easily inserted in place and removed when desired. The spring rs and i2 by which the crystal and the disks are supported, firmly but resiliently support these parts, and an effective and thoroughly practicable structure results.

To enclose the crystal and associated parts, a metallic domed casing or enclosure l may be provided, the same being engaged in and supported by the flange 3 at the edge of a bottom member 2 of metal in which the base i is mounted.

- While I have described one embodiment of the invention, it will be obvious that various changes may be made in the same without departing from the spirit of the invention. For example, while I have shown the two clamping fingers lo and 12 as being connected or attached externally of the casing to contact elements onv a single plug, it will be obvious that the fingers can also be caused to terminate on the outside of the casing in independent pins or other terminal members to enable the crystal to be suitably connected into a circuit. Other changes in the structure will be apparent to those skilled in this art and such changes are contemplated as being within the scope of the claims appended hereto.

What I claim is:

1. A crystal holder comprising, a base, a pair of resilient contact fingers secured in and arising from the base, a pair of dished metallic disks clamped between the fingers, the disks having concave faces disposed facially toward one another, and a metallic-faced crystal clamped between the disks and in contact with marginal edge portions of said disks.

2. A crystal holder comprising, a base, a pair of resilient clamping fingers arising from the base, a metallic-coated crystal, a pair of metal disks between which the crystal is sandwiched, each of said disks being of concavo-convex form and having an annular, flat marginal edge portion, the concave faces of the disks being directed toward the faces of the crystal, and the annular flanges on said disks being in contact with the opposite faces of the crystal.

3. In a crystal holder, a pair of metallic disks, a crystal disposed flatwisely between the faces of the disks, the disks having marginal edge portions only in contact with the faces of the crystal, the central portion of each disk being outwardly distended, and a pair of resilient clamping fingers embracing the disks and crystal between them, said resilient clamping fingers engaging the disks at a substantially central point thereof.

4. In a crystal holder as provided in claim 3, wherein a depression is provided at the center of the outwardly distended part of each disk for the reception of a part of each clamping finger, and the disks and crystal held between them are of substantially circular shape.

5. A crystal holder comprising, a base of insulating material, a pair of contact fingers extending through and arising from the base, a pair of dished circular metallic disks clamped between the fingers, the disks having concave faces disposed facially toward one another, said 'disks each having an annular flat flanged edge and a metallic-faced crystal clamped between the flanged edges of the disks and having its coated faces in contact with marginal edge portions of said disks.

6. A crystal holder comprising, a base, a pair of resilient clamping fingers arising from the base, a circular metallic-coated crystal, a pair of circular metal disks between which the crystal .is sandwiched, each of said disks being of concavo-convex form and having an annular, flatmarginal edge portion, the concave faces of the disks being directed toward the coated faces of the crystal, the annular flanges on said disks being in contact with the opposite coated faces of the crystal, and each disk being provided with a central depression for engagement by one of the clamping fingers.

'7. A crystal holder comprising, a base of in- .sulating material, said base provided with an integrally-formed plug portion, a metallic cap mounted at the free end of said plug portion, a stem extending axially through the base and through the plug portion, one end of said stem being connected to the cap, a spring finger attached to the second end of the stem, a sleeve surrounding the plug at a point remote from the cap, said sleeve being provided with a spring finger extending from it and passing through and emerging from the base, a crystal, and a pair of metal disks between which the crystal is sandwiched, said disks being disposed between the spring fingers and supported thereby with the crystal clampingly held between the disks.

WALTER E. KUENSTLER.

REFERENCES CITED The following references are of record in the file of this patent:

5 UNITED STATES PATENTS Number Name Date 2,078,284 Schrader et a1. Apr. 27, 1937 2,229,172 Hawk Jan. 21, 1941 10 2,429,414 Kuenstler Oct. 21, 1947 

